Edge Fluorescing Acrylic Light Bar Display for Transportation Refrigeration Units

ABSTRACT

An indicator display (20) comprises a fluorescent plastic first member (30) of a first color and having a first face (40) and a fluorescent plastic second member (32) of a second color, different from the first color, and having a first face (42). One or more first light emitting diodes (60) are between the first member and the second member and positioned to illuminate the first member preferentially to the second member. One or more second light emitting diodes (62) are between the first member and the second member and positioned to illuminate the second member preferentially to the first member.

CROSS-REFERENCE TO RELATED APPLICATION

This is a divisional of U.S. patent application Ser. No. 15/726,741,filed Oct. 6, 2017, entitled “Edge Fluorescing Acrylic Light Bar Displayfor Transportation Refrigeration Units” which claims benefit of U.S.Patent Application No. 62/418,518, filed Nov. 7, 2016, and entitled“Edge Fluorescing Acrylic Light Bar Display for TransportationRefrigeration Units”, the disclosure of which is incorporated byreference herein in its entirety as if set forth at length.

BACKGROUND

The disclosure relates to transport refrigeration. More particularly,the disclosure relates to status lights for trailers and containers.

Often, transport refrigeration units (TRU) will have external statusdisplays. Key examples involve truck boxes, refrigerated trailer boxes,and refrigerated intermodal containers (which may be carried ontrailers). In trailer situations, the display may be positioned so as tobe visible to the driver seated in the truck or tractor cab (e.g., via aside or center rear view mirror).

One example is found in U.S. Pat. No. 8,111,250. Other indicatorscomprise a binary status indicator (often termed “light bar”) such aswhere two groups of light emitting diodes (LED) are behind differentcolor lenses (e.g., green and amber) so that green light is used toindicate normal operational condition and amber light is used toindicate an abnormal condition needing further investigation by thedriver. The indicator may be triggered in response to one or more ofnumerous specific abnormal conditions, including: low-fuel in a unithaving a genset; engine over temperature; cargo box out of set pointrange; and mechanical faults such as high pressure in the refrigerationsystem.

Separately, fluorescent dye-doped acrylics have been developed. Earlyefforts are reflected in U.S. Pat. Nos. 3,276,216 and 3,928,226 and suchmaterials were commercialized under the trademark LISA of the formerMobay Chemical Corporation, but are now available from numerous sourcesin multiple colors and typically identified as “fluorescent castacrylic”. These acrylics are used, inter alia, in edge-lit signage.

SUMMARY

One aspect of the disclosure involves an indicator display comprising: afluorescent plastic first member of a first color and having a firstface; and a fluorescent plastic second member of a second color,different from the first color, and having a first face. One or morefirst light emitting diodes are between the first member and the secondmember and positioned to illuminate the first member preferentially tothe second member. One or more second light emitting diodes are betweenthe first member and the second member and positioned to illuminate thesecond member preferentially to the first member.

In one or more embodiments of any of the foregoing embodiments, the oneor more first light emitting diodes are on a first strip or tape and theone or more second light emitting diodes are on a second strip or tapefacing oppositely to the first strip or tape.

In one or more embodiments of any of the foregoing embodiments, one ormore of: the first and second members are fluorescent dye-doped acrylic;the first member first face and second member first face are coplanar;and the first member first face and second member first face bearrelieved indicia.

In one or more embodiments of any of the foregoing embodiments, theindicator further comprises a light sensor.

In one or more embodiments of any of the foregoing embodiments, thelight sensor is between the first member and the second member.

In one or more embodiments of any of the foregoing embodiments, thelight sensor is a phototransistor.

In one or more embodiments of any of the foregoing embodiments, atransport refrigeration system comprises the indicator display andfurther comprises a container having an interior and an exterior and arefrigeration system positioned for cooling the interior. The indicatoris positioned on the exterior.

In one or more embodiments of any of the foregoing embodiments, thetransport is a trailer.

In one or more embodiments of any of the foregoing embodiments, thetransport refrigeration system further comprises a controller configuredto operate the indicator: in a first condition wherein the one or morefirst light emitting diodes are on and the one or more second lightemitting diodes are off; and in a second condition wherein the one ormore first light emitting diodes are off and the one or more secondlight emitting diodes are on.

In one or more embodiments of any of the foregoing embodiments, thecontroller is configured to detect an abnormal situation and, responsiveto the detecting, switch the indicator from the first condition to thesecond condition.

In one or more embodiments of any of the foregoing embodiments, theabnormal situation is selected from the group consisting of a low-fuelsituation, a loss-of-refrigerant situation, engine over temperature,cargo box out of set point range, and high pressure in the refrigerationsystem.

The details of one or more embodiments are set forth in the accompanyingdrawings and the description below. Other features, objects, andadvantages will be apparent from the description and drawings, and fromthe claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view of an indicator display.

FIG. 2 is a cutaway via of the display of FIG. 1 taken along planeII-II.

FIG. 2A is an enlarged view of a portion of the display of FIG. 2.

FIG. 2B is an enlarged view of a portion of the display of FIG. 2.

FIG. 2C is an enlarged view of a portion of the display of FIG. 2.

FIG. 3 is a plan view of an LED tape.

FIG. 4 is a side view of a truck and refrigerated trailer combination.

FIG. 5 is a top view of the combination of FIG. 4.

Like reference numbers and designations in the various drawings indicatelike elements.

DETAILED DESCRIPTION

FIG. 1 shows an indicator display 20 comprising a housing 22 and adisplay unit 24 held by/within the housing. The housing has an openfront end through which the display unit is visible. The exemplaryhousing may be molded or machined plastic, machined, or bent metal, orthe like. Wiring 26 extends from the display unit through the housing toa connector 28. Alternatively, the connector 28 may be mounted on thehousing and a separate cable or other wiring may connect thereto. As isdiscussed further below, the display unit 24 includes a first portion 30and a second portion 32 for respectively displaying two different statusindicia.

As is discussed further below, the first and second portions may beformed as respective first and second fluorescent plastic members (e.g.,the aforementioned fluorescent dye-doped acrylics) of differentcoloration which are selectively lit via light emitting diodes (LEDs)(discussed below). The display unit portions may also have written orother graphical indicia which become apparent, or at least moreprominent, when lit. Exemplary respective indicia 34 and 36 of the twoportions may be formed such as via engraving or molding-in recesses tofirst surfaces 40 and 42 (FIG. 2) of the two portions. Engraving orother contouring may leave facets that increase the surface area forlight to pass.

Regions of the first surfaces 40 and 42 away from the indicia may bemasked such as via paint 150 (FIG. 2A). Additionally or alternatively,other surfaces of the portions 30, 32 may have reflective or absorptivecoatings or be in contact with members having reflective or absorptiveproperties. One example is an absorptive (e.g., matte black) coating ormaterial 152 (FIG. 2B) on the backsides of the portions 30, 32 or on themating front face of the rear wall of the housing. This absorptivematerial prevents fluorescing of the members due to ambient lightentering the front faces and then reflecting back. Transverse surfaces(e.g. along or of the interior surfaces of the perimeter wall portionsof the housing may bear a reflective coating or material 154 (FIG. 2C)(e.g., white or metallic).

Also a separate pre-formed housing is shown, alternative embodiments maylack a housing or have an in situ formed housing. For example, thefluorescent plastic may be wrapped with tape or painted or otherwisecoated. In the illustrated example, the first portion 30 is provided toindicate a normal or acceptable condition; whereas, the second portion32 is configured to provide an alert or warning. In the exemplaryembodiment, the surfaces 40 and 42 are flat and coplanar with eachother. FIG. 1 also shows a light sensor 50 between the first portion 30and second portion 32. An exemplary light sensor is a phototransistor-,photodiode-, or photoresistor-type sensor. Alternative mountingpositions for the sensor 50 (if present at all) may include otherlocations on the housing 22.

FIG. 2 shows one or more first LEDs 60 positioned to illuminate thefirst portion 30 preferentially to the second portion 32 (i.e., morethan the second portion, if the second portion at all). One or moresecond LEDs 62 are positioned to illuminate the second portion 32preferentially to the first portion. In this example, to provide thepreferential lighting, the first diodes face toward an edge 64 of thefirst portion 30 and away from an adjacent edge 66 of the second portion32. The second LEDs face oppositely. Thus, in this exemplary embodiment,both sets of LEDs are accommodated in a gap between the portions 30 and32. As is discussed further below, the gap may largely be filled with anin situ formed member such as a body 68 of potting material (e.g., curedin place). An exemplary potting material is an optically clear epoxy. Anexemplary two-part epoxy is available from M.G. Chemicals, Ltd.,Burlington, Ontario, Canada, under product no. 8322. The exposed frontface of the body 68 may be covered by the paint 150 or by a separatematerial 160 (FIG. 2A) (e.g., tape) to prevent infiltration of ambientlight to reduce unintended fluorescing. The material 160 may have a hole162 (FIG. 1) through which the sensor 50 is exposed or protrudes.

Arrays of the LEDs may be pre-formed as respective strips or tapes 70,72. Exemplary strips or tapes comprise a strip or tape carrier 74 withthe associated LEDs mounted on one face of the carrier. Exemplary LEDtapes are commercially available pre-formed with conductive traces 80(FIG. 3) on the carrier. When the tapes are cut at predeterminedlocations 82, the traces leave contacts 84 which may be mated to awiring connector (not shown). Alternative embodiments may have discreteLEDs or LEDs mounted on circuit boards rather than tapes. Wiringextending from such connector may form or be connected to the wiring 26and/or connector 28.

FIG. 2 also shows the light sensor 50 and its wiring which may passthrough the body 68 to become or be connected to the wiring 26 andconnector 28. Thus, in an exemplary embodiment, the connector 28includes one or more separate contacts for independently powering thetwo groups of light emitting diodes and one or more contacts for sensoroutput. Yet other functions may be integrated with the indicator display20 but are not discussed herein.

In the exemplary embodiment, commensurate with the binary statusindication, the first portion 30 comprises plastic doped with a greenfluorescent dye so that when lit the green universal color of normaloperating condition is displayed. FIG. 1 shows three “OK” indicia 34 tobe illuminated for normal operating condition. The second portion 32 maybe otherwise similar material but doped with a different color such asred or amber to indicate an abnormal/alert condition. FIG. 1 shows an“ATTENTION” indicia 36 to be illuminated for an abnormal/alert condition(e.g., a situation selected from the group consisting of a low-fuelsituation, a loss-of-refrigerant situation, engine over temperature,cargo box out of set point range, and high pressure in the refrigerationsystem). With the two portions being fluorescent dope, both sets of LEDsmay be the same color such as a basic white LED.

FIG. 4 shows a refrigerated transport system (transport refrigerationsystem) 200. The exemplary system 200 is a tractor 202 and trailer 204combination. The exemplary tractor 202 comprises a cab 206 and apowertrain (e.g., diesel engine-based) for driving one or more sets ofwheels. In the exemplary semi-trailer configuration, a forward portionof the trailer 204 is pivotally mounted atop a rear portion of thetractor and supported thereby. The trailer comprises a container or box210 having an interior 212 and an exterior 214. The trailer furthercomprises a refrigeration system 220 positioned for cooling theinterior. An exemplary refrigeration system 220 is mounted in anequipment box 222 along a front of the container.

The exemplary refrigeration system 220 is a vapor compression systemcomprising a compressor for driving refrigerant flow along arecirculating refrigerant flowpath. In normal cooling mode, therefrigerant flowpath proceeds downstream from an outlet or dischargeport of the compressor through a heat rejection heat exchanger to rejectheat to the external environment (e.g., via a fan-forced externalairflow). Refrigerant may then be expanded such as in an expansiondevice (e.g., electronic expansion valve, thermal expansion valve,orifice, capillary device, or the like) and passed to a heat absorptionheat exchanger in thermal communication with the interior (e.g., via afan-forced internal airflow). After absorbing heat, refrigerant mayreturn to a suction port or inlet of the compressor. An exemplarycompressor is driven by an integral electric motor which, in turn, ispowered by an internal combustion engine generator (genset). Theforegoing is merely one basic example of a refrigeration system.

The exemplary display 20 is mounted proximate a forward driver's sideend of the container so as to be visible by the driver seated in the cabusing the driver's side rear view mirror 240 (FIG. 4) (e.g., within 0.1m of the corner of the footprint of the container).

FIG. 4 further shows a controller 250. The controller may receive userinputs from an input device (e.g., switches, keyboard, or the like) andsensors (not shown, e.g., pressure sensors and temperature sensors atvarious refrigeration system locations, fuel, temperature, or othersensors associated with the genset, and/or other system, component, oroperational parameter errors). The controller may be coupled to thesensors and controllable system components (e.g., valves, the bearings,the compressor motor, vane actuators, and the like) via control lines(e.g., hardwired or wireless communication paths) and similarly coupledto one or more output devices (and/or have integrated output devices).In the exemplary embodiment, the controller may be coupled to theindicator 20 via the connector 28 mating with a complementary connectoron the controller. The controller may include one or more: processors;memory and/or storage (e.g., for storing program information forexecution by the processor to perform the operational methods and forstoring data used or generated by the program(s)); and hardwareinterface devices (e.g., ports) for interfacing with input/outputdevices and controllable system components. The exemplary indicatorwiring and controller programming are effective to allow the controllerto independently control the first and second LEDs or at leastinterdependently control them so that one group will be off when theother is on.

Thus, the controller may be configured (e.g., via programming or hardcoding) to power the first LEDs in a normal situation and the secondLEDs in one or more abnormal situations. Thus, the controller may beconfigured to determine such abnormal situations (e.g., low-fuel in aunit having a genset, engine over temperature, cargo box out of setpoint temperature range, and mechanical faults such as abnormally low orhigh pressure in the refrigeration system and/or other indication ofloss of refrigerant) and responsively switch between the two conditionsof the indicator display.

The system may be made using otherwise conventional or yet-developedmaterials and techniques.

Various parameters of manufacture, configuration, and use may be guidedby the particular unit to which the display 20 is applied. For example,display 20 may be made as a drop-in-replacement for an existing LEDdisplay wherein groups of LEDs directly illuminate through lenses. Insuch a situation, the existing transport refrigeration system may beprovided and the existing display removed. The replacement display 20may be mechanically installed in place and electrically connected viathe wiring 26 and/or connector 28 to the existing controller (e.g., inthe equipment box). In other situations, the display 20 may be added asa retrofit of a system either lacking a display or with the retrofitpreserving both the original display and the added display 20. In yetother systems, the display 20 may be included as an original equipmentmanufacture (OEM) feature.

The use of “first”, “second”, and the like in the description andfollowing claims is for differentiation within the claim only and doesnot necessarily indicate relative or absolute importance or temporalorder. Similarly, the identification in a claim of one element as“first” (or the like) does not preclude such “first” element fromidentifying an element that is referred to as “second” (or the like) inanother claim or in the description.

One or more embodiments have been described. Nevertheless, it will beunderstood that various modifications may be made. For example, whenapplied to an existing basic system, details of such configuration orits associated use may influence details of particular implementations.Accordingly, other embodiments are within the scope of the followingclaims.

1. An indicator display (20) comprising: a fluorescent plastic firstmember (30) of a first color and having a first face (40) and an edge(64); a fluorescent plastic second member (32) of a second color,different from the first color, and having a first face (42) and an edge(66); one or more first light emitting diodes (60) between the firstmember edge and the second member edge and positioned to illuminate thefirst member edge preferentially to the second member edge; and one ormore second light emitting diodes (62) between the first member edge andthe second member edge and positioned to illuminate the second memberedge preferentially to the first member edge.
 2. The indicator displayof claim 1 wherein: the one or more first light emitting diodes are on afirst strip or tape (70); and the one or more second light emittingdiodes are on a second strip or tape (72) facing oppositely to the firststrip or tape.
 3. The indicator display of claim 1 wherein: the firstand second members are fluorescent dye-doped acrylic; the first memberfirst face and second member first face are coplanar; and the firstmember first face and second member first face bear relieved indicia(34, 36).
 4. The indicator display of claim 1 further comprising: alight sensor (50).
 5. The indicator display of claim 4 wherein: thelight sensor is between the first member and the second member.
 6. Theindicator display of claim 4 wherein: the light sensor is aphototransistor.
 7. (canceled)
 8. (canceled)
 9. The indicator display ofclaim 1 wherein: a first condition the one or more first light emittingdiodes are on and the one or more second light emitting diodes are off;and a second condition the one or more first light emitting diodes areoff and the one or more second light emitting diodes are on. 10.(canceled)
 11. (canceled)
 12. A method for using the indicator displayof claim 1, the method comprising: operating in a first conditionwherein the one or more first light emitting diodes are on and the oneor more second light emitting diodes are off; and operating in a secondcondition wherein the one or more first light emitting diodes are offand the one or more second light emitting diodes are on.
 13. The methodof claim 12 further comprising: detecting, via a controller (250), anabnormal situation; and responsive to the detecting, switching from thefirst condition to the second condition.
 14. (canceled)
 15. (canceled)16. (canceled)
 17. (canceled)
 18. The indicator display of claim 1wherein: the one or more first light emitting diodes are a firstplurality; and the one or more second light emitting diodes are a secondplurality.
 19. The indicator display of claim 2 wherein: the one or morefirst light emitting diodes are a first plurality; and the one or moresecond light emitting diodes are a second plurality.
 20. The indicatordisplay of claim 2 wherein: the first strip or tape (70) and the secondstrip or tape (72) are embedded in a body (68).
 21. The indicatordisplay of claim 20 wherein: the body (68) is an epoxy.
 22. Theindicator display of claim 20 wherein: a face of the body (68) iscovered by paint (150) or by a separate material (160) to preventinfiltration of ambient light.
 23. The indicator display of claim 20wherein: the one or more first light emitting diodes are a firstplurality; and the one or more second light emitting diodes are a secondplurality.
 24. The indicator display of claim 20 wherein: the firstmember first face and second member first face bear relieved indicia(34, 36); and the first member first face and second member first faceaway from the relieved indicia are masked via paint (150).